Fighting Legionnaires' Disease

New research indicating how the immune system fights bacteria causing the severe pneumonia Legionnaires' disease is reported in the March issue of Nature Immunology.

After infecting cells, the bacteria (Legionella pneumophila) that causes Legionnaires' disease, can hide from the body's immune defenses by living and multiplying in sealed vacuoles inside cells. The immune system detects bacteria that leave the vacuole and activates 'suicide machinery' to eliminate the infected cell. However, exactly how the immune system detects these bacteria is not understood.

Craig Roy and colleagues now demonstrate that the protein Birc1e is important for the detection of Legionella infection. They have pinpointed regions of Birc1e that are needed to 'sound the alarm' and show Birc1e activates components of the 'suicide machinery' after Legionella infection.

This information enhances our understanding of how the body fights off infection by a potentially lethal microbe.